SW5230901_Response To Comments_20240404

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TIMMONS GROUP
YOUR VISION ACHIEVED THROUGH OURS.
Project: NCNG Camp Butner BOM Yard Expansion
Date: 04/04/2024
Contact: Jake Lewis, PE
Phone: [phone]
Email: [e-mail]
Comments from NCDEQ review has been addressed below. Our responses are in red.
Construction Document Submittal First Submittal Comments—03/06/2024
NCDEQ REVIEW COMMENTS
Jim Farkas (919-707-3646,jim.farkasaC ncdenr.govi
1. From the prior design,the bypass weir in the outlet structure was removed. Since this structure
was removed, the invert of the lowest bypass device (which determines the elevation of the
temporary ponding surface/design volume) is now the weir/top of the riser structure located at
elevation 458.0'. Please either:
a. Include a bypass device with invert at elevation 457.61', revising any calculations to
reflect this change in the design.
b. Revise the calculations, Supplement-EZ Form, and O&M Agreement Form to reflect the
temporary ponding surface/design volume at elevation 458.0' (at a minimum,you
would need to revise Line 18 of the Drainage Areas Page of the Supplement-EZ Form,
Lines 25, 25, &40 on the Wet Pond Page of the Supplement-EZ Form,the temporary
pool elevation on the O&M Agreement Form,the drawdown calculations (to use the
new design volume and head),the snap tool (as the SCM will now be oversized), and
any other calculations that would be impacted by this.
TG Response: We are choosing Option B,the temporary pool elevation is 458.0(at the top of the
riser) and the percent of full size is 138%.We have updated line 18 of the Drainage Areas Page
of the Supplement-EZ Form, Lines 2, 25, 35 and 40 on the Wet pond Page of the SUPP-EZ,the
temporary pool elevation on the O&M Agreement Form, the drawdown calculations&wet pond
sizing sheet and the SNAP tool accordingly. Updated calculations and forms are attached,there
were no changes to the plan sheets.
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